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The chaingun always fires in pairs of hitscan shots, as long as the player has two bullets or more. Each bullet inflicts 5-15 points of damage. The first two shots in a volley will always be exactly on target, but if the trigger is held down, later shots will suffer from the same dispersal as pistol shots (standard deviation around 2°, to a maximum of ±5.5°).

The chaingun's rapid rate of fire means that a single enemy caught in its hail of bullets will have little or no chance to retaliate. This is effective against most monsters, particularly demons and cacodemons (but not boss monsters, whose pain chance tends to be very low). The weapon is also highly effective at mowing down hordes of zombies or imps. Because its recoil does not affect the first two shots, it is an ideal weapon for sniping, as the player can tap the fire button for accurate two-shot bursts. The chaingun is also good for finishing off monsters that have been weakened by attacks from more powerful weapons.

However, under most circumstances, ammo consumption must be carefully monitored, as the chaingun's relatively high rate of fire can deplete one's ammo quickly, especially since many of the more powerful monsters can take literally dozens of bullets to kill. In particular the player's inventory only allows for a limited supply of bullets compared to other types of ammunition, plus bullets are scarce compared to shotgun shells. For general combat, the slower-firing (but more powerful) shotgun is usually preferred, allowing the player to stockpile bullets for situations where the chaingun's high rate-of-fire is useful.

As with the rocket launcher and BFG9000, the first-person chaingun sprite is slightly too large for the screen, and can only be viewed with a level or resource editor.

The target of chaingun fire often appears to turn and shuffle rapidly in place, due to the continual interruption of its sprite sequences. Doom's instruction manual refers to this motion as "the chaingun cha-cha."

The chaingun first appeared in the Doom press release beta. Its graphic was slightly different, in that the tips of the barrels did not extend past the barrel band.

Wolfenstein 3D, the game id Software released immediately before Doom, included a similar chaingun. However, it was a blue color.

If the Doom chaingun is associated with real weaponry, it is a Gatling-style weapon with rotating barrels similar to a minigun. An actual chain gun only has a single barrel and uses an electric motor to drive a chain connected to the bolt assembly, moving it back and forth to load, fire, extract, and eject ammo cartridges.

Unlike most real-world gatling-style weapons such as miniguns, the Doom chaingun has a pistol-grip styled handle and trigger group similar to those found on assault rifles or submachine guns, rather than being an infantry-portable minigun seen in the films Predator (1987) and Terminator 2: Judgement Day (1991). As a result of these characteristics, it's implied that the chaingun can be held single-handedly like a pistol by a muscular user (as illustrated by Doom cover art, the Heavy Weapon Dude, or by its appearance in the Doom comic) or perhaps held like an assault rifle.

As with all firearm hitscan attacks, the average damage inflicted per bullet by the player's weapon is slightly higher than that of monsters using equivalent attacks.

In the Saturn port, the chaingun fires much faster than it normally would.

In the Game Boy Advance port of Doom II, the weapon fires only one shot at a time, and has a somewhat higher overall rate-of-fire. However, the accuracy of the weapon is significantly lower, due to the fact that the dispersal is cone-shaped rather than fan-shaped, and single shots have the same dispersal as automatic fire.

While the chaingun does not have a reload animation, it makes sense in this particular case, as opposed to the other traditional firearms. It is implied to be belt-fed due to its name and functionality, and that fact is corroborated by the Heavy Weapons Dude's appearance in Doom II (the weapon's pickup sprite is somewhat ambivalent in this regard; it has what appears to be a clip inserted into the bottom of the weapon, though this could be a box that holds an ammo belt.).

This table assumes that all calls to P_Random for damage, pain chance, blood splats, and bullet dispersal are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). Any resulting errors are probably toward the single-bullet average, as they introduce noise into the correlation between the indices of "consecutive" calls.

In the case of continuous fire, the target must be close enough to compensate for the weapon's recoil.

Assumes that direct hits are possible, which does not occur in any stock map.

In Doom 64, the Chaingun is depicted with longer perforated barrels and a worn blue tone (rather than its counterpart's polished steel appearance). The handle and trigger group is also more similar to those used on real-world minigun-style weapons. Additionally, it has a smaller blue muzzle flash. The pickup sprite has a somewhat rusty appearance as well. When fired at a consistant rate, the screen will jerk up and down rapidly.